1. Field of the Invention
This invention relates to package tying machines, and more particularly to clutch lock out and clutch release mechanisms for such machines.
2. Description of the Prior Art
The interest in the safety and overall working environment of the operator of package tying machines has motivated tying machine manufacturers to incorporate specialized clutch lock out mechanisms in such machines. That is, mechanical or electrical safety devices are incorporated in tying machines to prohibit any inadvertent operation such as can happen when a machine has been turned off and the cycle-initiating hand lever or foot pedal is inadvertently tripped thereby causing the machine to undesirably cycle without notice when the machine is again turned on. Various electrical lock out systems have been utilized on prior art package tying machines, but these have been found undesirable as being either unduly expensive or unreliable because of the occasional failure of associated electrical components.
Additionally, there has been a continuing desire to eliminate as much operating noise as possible from package tying machines, especially in those instances where multiple tying machines are in tandem and kept continually running, such as in high volume, package-shipping operations. When the clutch is engaged in many prior art machines, various sharp reports are produced such as when the clutch plate members snap together and when the associated clutch-engaging components change positions.
Reference is made to U.S. Letters Pat. Nos. 1,201,688; 2,361,742; and 2,898,847 wherein the structure and operation of typical prior art clutch-engaging mechanisms for tying machines are described. Reference is also made to U.S. Letters Pat. Nos. 1,606,290 and 2,898,847 wherein the operation of typical prior art package tying machines are described. Generally, the prior art machines included a wedge-shaped release lever -- connected to the machine's cycle-initiating foot pedal or hand lever -- that was instantly removed from between the machine's clutch operating lever (forked clutch lever) and the cam follower lever thereby causing the clutch to become engaged, but at the same time causing both undesirably loud, mechanical noises and the possibility of self-releasing of the cam, while providing no effective clutch lock out control. Additionally, the prior art clutch release mechanisms provided no simple adjustment when associated clutch parts become worn with use.